// 用于撑开零高容器, 让零高容器放置内容
// block-height(1, 2)
// block-height({width, height})
mixin block-height(...args)
  -var contentWidth = 0
  -var contentHeight = 0

  if typeof args[0] === 'object'
    -contentWidth = args[0].width
    -contentHeight = args[0].height
  else 
    -contentWidth = images[0].width
    for idx in args
      -contentHeight += images[idx].height

  section(style=`text-align:center;height:0;line-height:0;width:100%;margin:-1px auto 0;pointer-events:none;visibility:visible`)
    svg(style=`display:inline;visibility:visible`, viewBox=`0 0 ${contentWidth} ${contentHeight}`)
    block
